This invention relates generally to tanks for the storage of liquids, and more particularly to cylindrical tanks fabricated from polymer materials and a method for making same.
Tanks for the storage of liquids have been constructed in a variety of ways from a variety of materials. In one common application, the storage of hydrocarbons, such as gasoline and other petroleum products, the tanks have conventionally been fabricated out of steel or fiberglass, most commonly with a rigid single wall. In many applications this constructions has proved reasonably satisfactory, although the cost of tanks of those constructions has been substantial. Additionally, with increasing age, steel tanks may begin to rust due either to water accumulating on the inside of the tank with the hydrocarbon, or from soil moisture. For these reasons there has been a need for alternative construction of such tanks, whether for hydrocarbons or for the storage of other types of liquids, and whether fabricated of single or multiple wall construction.
Several methods of manufacturing such tanks have been developed, including those disclosed by David T. Palazzo, the inventor of the present invention, in U.S. Pat. No. 4,640,439 and its progeny, and in his U.S. Pat. No. 5,816,435, to which the present invention is related. While the materials and processes disclosed in those prior patents have been satisfactory in many respects, a need has existed for improved efficiency in manufacturing those tanks.